Electric-current receiver



June 24 19240 1,498,863 v c2. w. BURROWS ELECTRIC CURRENT RECEIVER Filed March 11, 1922 INVEfJ T0}? Char/es Wfiurmws er k Patented June 24-, 1924.

CHARLES W. BURROWS, OF NEW YORK, N.'Y.

ELECTRIC-CURRENT RECEIVER.

Application filed March 11, 1922.

T all whom it may concern:

Be it known that 1, CHARLES W. BUR- ROVVS, a citizen of the United States, residing at New York, in the county of New York, State of New York, have invented certain new and useful Improvements in Electric-Current Receivers, of which the following is a description, reference being had to the accompanying drawing and to the figures of reference marked thereon.

This invention relates to electric current receivers and on account of the construction which will be hereinafter described, it is especially adapted for the receiving of currents in a wireless system. although of course it is readily appreciated that the receiver is not limited to this particular use.

Since in wireless work the electric currents involved are variable in their characteristics and many times these currents are exceedingly weak, the receiver must be highly sensitive in order to pick up these delicate sound waves.

It is, therefore, the principal object of my invention to provide a receiver in which very high sensibility to weak currents has been secured.

Another object of my invention is to provide a receiver which is strong and which is shaped to form easily to the operators ear so that the same may be worn for a number of hours without. discomfort.

These and other objects have been secured by careful attention to the scientific principles involved in a receiver of the class described. My invention will be best understood by reference to the drawing in which:

Figure 1 is a plan view of the receiver withthe diaphragm and ear cap removed.

Figure 2 is a section on the line 2/2 of Fig. 1 with the diaphragmand ear cap in place. 1 c

Figure 3 is a plan view of the magnet used in the receiver. I

Figure 4 is a plan view of the magnet clamp. 1

Figure 5 is aview of'Fig. 4 looking in the direction of the arrow. v

Figure 6 is an enlarged section on the line 6/6 of-Fig. 1 but without the. clamping screw.

Referring more particularly to the details wherein like numbers refer to corresponding parts in the'various views, the ei e i ma e up 0 .a.. *$i 1levingi r Serial No. 543 ,1-16.

body part 1 and an ear cap 2 fastened to the body part in any suitable manner, such as by threads 3. Pllaced within the body of the casing l is a magnet 4, which is circular in shape and formed so as to be placed in the casing edgewise. As will be seen the magnet 4 is rectangular in shape and by forming it so that it will stand edgewise within the casing, a better space factor between the limbs of the magnet is obtained with appreciable reduction in the self-de-' magnetization. Furthermore, more space is provided within the central portion of the magnet for the windings carried on the magnet pole piece cores. It will be noted that from the point 6 the magnet ends are bent inwardly away from the casing and that these bent ends are straight from the point of bend out to the end of the magnet. This construction is for the reception of magnet clamps 7 which are formed as rights and lefts. The construction of these clamps is more clearly shown in Figs. 4 and 5, from which it will be seen that the clamp has a flat bottom 8 which rests on the bottom of the body of the casing and is held thereto by a screw 9 passing through the ta ped hole 10. An upright portion 11 of the 0 amp engages the inner side 12 of the magnet 4 and is' then bent over the upper edge 13 of the magnet end and then is turneddownward at 14 to engage the back edge-0f the end of the magnet.

' It will be seen from this construction that the major portion of the end of the magnet is tightly gripped by the clamp so that an exceedingly good contact is made with the pole end of the magnet, thereby enabling the maximum amount-of flux to be taken up from the magnet andcarried to the cores of the windings. V

- The clamps are turned upward at their other extremity as indicated by l5'forming cores forthe electromagnet windings" 16. In my construction I have preferred to make the electromagnets relatively long and thin instead of short and fat, as I have found that this construction gives a minimum resistanceof the winding with a maximum number'of turns. I

I'prefer to make the casing 1' of moulded insulating material and when so made I mould integral withthe body part '1, a bridge 17. Moulded within the bridge 17 par (is f is clearly shown in Fig. 6. This insert is tapped at 19 for a clamping screw 20 which is adapted to engage a terminal that is inserted through the hole 21 in the side of the body 1. The insert 18 has preferably connected integral with it, a terminal 22 to which one lead of the electromagnet 16 is connected. The side walls of the body 1 have holes or depressions 25 therein for the reception of support pins whereby the receiver may be carried on a suitable head band.

As shown in Figure 2 a diaphragm 23 rests against the outer rim 24: of the body 1 and is securely fastened to the rim 24: by the screwing on of the ear piece 2 to the body 1. It will be understood by one skilled in this art that the diaphragm 23 may be held in working relationship to the end of the cores 15 by some other suitable means instead of by the ear piece, but what I desire to point out particularly is that my construction and arrangement of the permanent magnet 4:, the integral core and clamping members 7 making a large area of contact with the magnet, etc. as has been pointed out, brings to the end of the cores 15 a maximum amount of magnetic flux which is differentially acted on by the electromagnetic windings 16, whereby I am able to use a thicker diaphragm than is ordinarily used in receivers made especially for wireless work. A thicker diaphragm has a natural period of Vibration higher than a thinner one and when used in the combination as has been described, such a diaphragm is particularly sensitive to the high frequency wireless currents and in order to produce 'the greatest effect with the agents that I have described and by proportioning the air gap between the diaphragm and the core ends, I am enabled to choose a diaphragm of such stifiness that its restoring force per se due to its deflection is proportional to the change in magnetic field intensity of the field set up by the permanent magnet and the electromagnetic winding.

It will be apparent that numerous changes may be made in the various details without departing from the scope of my invention and the spirit of the appended claims.

Having thus described my invention, what I claim is: g I

1. In a device of the class described, a casing having a body part and an ear cap, a permanent magnet having its main portion circular in shape but having its ends bent inwardly in substantially a straight line from the point of bend, magnetic clamp members for engaging said straight magnet ,ends, said clamp members having integral projections with windings thereon, means for fastening the said clamps and windings thereon to said body part, means for making electrical connections to windings and a diaphragm associated with. said clamp projections, carrying the windings, and the ear cap.

2. In a device of the class described, a casing having a body part and an ear cap, a permanent magnet having its main portion circular in shape to conform to the interior contour of the body of the casing but having its ends bent inwardly in substantially a straight line from the point of bend, magnet clamp members having hook portions for fitting tightly over said straight magnet ends, said clamps having integral projcc tions extending upwardly from the bottom of the casing substantially in syn'imetrical K4 relation to the central opening in the body of the casing, windings on said projections, means for making electrical connections to said windings, means for fastening said clamps and windings thereon to said casing body and a diaphragm associated with said clamp projections and the ear cap.

3. In a device of the class described, a casing having a body part and an ear cap, a bridge within the body, said body and bridge being moulded integral from suitable insulation material, a permanent magnet having its main portion circular in shape but having its ends bent inwardly in substantially a straight line from the point of bend, said ends extending in close proximity to said bridge magnetic clamp members having hooks fitting tightly over said ends, said clamp members having integral projections extending upwardly from the bottom of said body part within the arch of the magnet, windings on said clamp pro jections, terminal connections for the winding carried by said bridge, means for fastening the clamps to said body and a diaphragm associated with said projecting clamp ends and the ear cap.

4:. In a device of the class described, a casing having a body part and an ear cap, a bridge within the body, said body and bridge being moulded integral from suitable insulation material, apermanent magnet having its main portion circular in shape but having its ends bent inwardly in substantially a straight line from the point of bend, said ends extending in close proximity to said bridge, magnetic clamp members having hooks fitting tightly over said ends, said hooks being formed so as to make a large surface contact with said magnet ends, said clamp members having integral projections extending upwardly from the bottom of said body part in substantially symmetrical relationship to the opening in the body of the casing, a winding on said clamp projections, terminal connections for the winding carried by said bridge, means for fastening the clamps to the body and a diaphragm secured to the outer edge of the body by said ear cap,

5. In a device of the class described, a casing having a body part and an ear cap, a permanent magnet rectangular in cross section and formed circularly to fit edgewise within said body part of the casing but having its ends bent away from the casing in straight lines from the point of bend, magnetic clamps fitting tightly over said ends and contacting with the major portion of one side, one edge and part of the other side of the ends, said clamps extending toward the central portion of the casing body and then turning upward to a point below the plane. of the edge of the body of the casing, windings on said upturned portions of the clamps, means for fastening the clamps to the casing, means for making electrical connection to said windings and a diaphragm held in working relationship to said clamp ends and windings thereon by said ear cap.

6. In a device of the class described, a casing having a body part and an ear cap, a one piece permanent magnet fitting within said body part of the casing, clamps of magnetic material fitting tightly over the ma or portion of the end surface of said magnets, said clamps extending toward the central portion of the casing and then turning upward to form electromagnet cores, windings on said cores, means for fastening the clamps to the casing, means provided for making electrical connections to said windings 7 and a diaphragm between said cores and ear cap.

7. In a device of the class described, a casing having a body part and an ear cap, a one piece rectangular shaped permanent magnet formed so as to fit edgewise into said casing, means for holding the magnet in place in the casing consisting of two one piece members terminating in hooks at one end for closely engaging the magnet ends and electromagnet cores at the other end, windings on said cores, terminal connections for said windings and a diaphragm held in working position between the cores and ear 8 In a device of the class described, the combination of a casing, having a body part and an ear cap, with a permanent magnet held within the casing by combined core and clamp members which engage the magnet ends over the major portion of their peripheral surface and which have electro magnetic windings on the core portions, and a diaphragm mounted on the body part of the casing between said cores and ear cap, the stiffness of said diaphragm being such that its restoring power per se is substantially proportional to the change in magnetic field intensity of the field produced by said permanent magnet and the electromagnetic windings.

In testimony whereof I afiix my signature.

' CHARLES W. BURROWS. 

